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disa [49]
4 years ago
11

In 2016, the population of the United States was approximately 3.24 x 10^8. It is expected that the population will be about 3.9

8 x 10^8 in 2050. Which shows the growth in population, written in scientific notation?
Mathematics
1 answer:
aleksandrvk [35]4 years ago
5 0

Answer:

7.4 x 10^7

Step-by-step explanation:

3.98 x 10^8 - 3.24 x 10^8 = 0.74 x 10^8 (not scientific notation, because it isn't full number)

0.74 x 10^8 ---> 7.4 x 10^7

   - got seven by counting the spaces it moved over (right decrease, while left increases)

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Water is being pumped into a conical tank that is 8 feet tall and has a diameter of 10 feet. If the water is being pumped in at
Deffense [45]

The rate of change of the depth of water in the tank when the tank is half

filled can be found using chain rule of differentiation.

When the tank is half filled, the depth of the water is changing at  <u>1.213 × </u>

<u>10⁻² ft.³/hour</u>.

Reasons:

The given parameter are;

Height of the conical tank, h = 8 feet

Diameter of the conical tank, d = 10 feet

Rate at which water is being pumped into the tank, = 3/5 ft.³/hr.

Required:

The rate at which the depth of the water in the tank is changing when the

tank is half full.

Solution:

The radius of the tank, r = d ÷ 2

∴ r = 10 ft. ÷ 2 = 5 ft.

Using similar triangles, we have;

\dfrac{r}{h} = \dfrac{5}{8}

The volume of the tank is therefore;

V = \mathbf{\dfrac{1}{3} \cdot \pi \cdot r^2 \cdot h}

r = \dfrac{5}{8} \times h

Therefore;

V = \dfrac{1}{3} \cdot \pi \cdot \left(  \dfrac{5}{8} \times h\right)^2 \cdot h = \dfrac{25 \cdot h^3 \cdot \pi}{192}

By chain rule of differentiation, we have;

\dfrac{dV}{dt} = \mathbf{\dfrac{dV}{dh} \cdot \dfrac{dh}{dt}}

\dfrac{dV}{dh}=\dfrac{d}{h} \left(  \dfrac{25 \cdot h^3 \cdot \pi}{192} \right) = \mathbf{\dfrac{25 \cdot h^2 \cdot \pi}{64}}

\dfrac{dV}{dt} = \dfrac{3}{5}  \ ft.^3/hour

Which gives;

\dfrac{3}{5} =  \mathbf{\dfrac{25 \cdot h^2 \cdot \pi}{64} \times \dfrac{dh}{dt}}

When the tank is half filled, we have;

V_{1/2} = \dfrac{1}{2} \times  \dfrac{1}{3} \times \pi \times 5^2 \times 8 =\mathbf{ \dfrac{25 \cdot h^3 \cdot \pi}{ 192}}

Solving gives;

h³ = 256

h = ∛256

\dfrac{3}{5} \times \dfrac{64}{25 \cdot h^2 \cdot \pi} = \dfrac{dh}{dt}

Which gives;

\dfrac{dh}{dt} = \dfrac{3}{5} \times \dfrac{64}{25 \cdot (\sqrt[3]{256}) ^2 \cdot \pi} \approx \mathbf{1.213\times 10^{-2}}

When the tank is half filled, the depth of the water is changing at  <u>1.213 × 10⁻² ft.³/hour</u>.

Learn more here:

brainly.com/question/9168560

6 0
3 years ago
I need help what is (-7) · (-5)= pls
Akimi4 [234]

Answer: 35

Step-by-step explanation:

7 x 5 is 35 and even though there are negatives 2 negatives form a positive

5 0
2 years ago
The product of eight and a number decreased by four is the same as eight plus five time the same number.
dedylja [7]

Answer:

The Answer is: The Number is 4

Step-by-step explanation:

Let n = the number.

Eight times a number minus 4 equals 8 plus 5 times the number.

8n - 4 = 8 + 5n

3n = 12

n = 4, the number is 4.

Proof:

8(4) - 4 = 8 + 5(4)

32 - 4 = 8 + 20

28 = 28

Hope this helps! Have an Awesome Day!! :-)

5 0
4 years ago
B+8b -5 -2b = 16 what does b equal
kotegsom [21]

Answer:

b=3

Step-by-step explanation:

b+8b -5 -2b = 16 Simplify

7b - 5 = 16 Add 5 on both sides

7b = 21 divide 7 on both sides

b = 3

8 0
3 years ago
Read 2 more answers
A bacterium in a petri dish multiplies by a factor of 2 every day. On day O,
balu736 [363]

Answer:

1,000,000,000 divided by 2

Step-by-step explanation:

if each is being multiplied by two, dividing this by two is the inverse operation.

5 0
3 years ago
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